cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

fb_sys_fops.c (2075B)

      1/*
      2 * linux/drivers/video/fb_sys_read.c - Generic file operations where
      3 * framebuffer is in system RAM
      4 *
      5 * Copyright (C) 2007 Antonino Daplas <adaplas@pol.net>
      6 *
      7 * This file is subject to the terms and conditions of the GNU General Public
      8 * License.  See the file COPYING in the main directory of this archive
      9 * for more details.
     10 *
     11 */
     12#include <linux/fb.h>
     13#include <linux/module.h>
     14#include <linux/uaccess.h>
     15
     16ssize_t fb_sys_read(struct fb_info *info, char __user *buf, size_t count,
     17		    loff_t *ppos)
     18{
     19	unsigned long p = *ppos;
     20	void *src;
     21	int err = 0;
     22	unsigned long total_size;
     23
     24	if (info->state != FBINFO_STATE_RUNNING)
     25		return -EPERM;
     26
     27	total_size = info->screen_size;
     28
     29	if (total_size == 0)
     30		total_size = info->fix.smem_len;
     31
     32	if (p >= total_size)
     33		return 0;
     34
     35	if (count >= total_size)
     36		count = total_size;
     37
     38	if (count + p > total_size)
     39		count = total_size - p;
     40
     41	src = (void __force *)(info->screen_base + p);
     42
     43	if (info->fbops->fb_sync)
     44		info->fbops->fb_sync(info);
     45
     46	if (copy_to_user(buf, src, count))
     47		err = -EFAULT;
     48
     49	if  (!err)
     50		*ppos += count;
     51
     52	return (err) ? err : count;
     53}
     54EXPORT_SYMBOL_GPL(fb_sys_read);
     55
     56ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
     57		     size_t count, loff_t *ppos)
     58{
     59	unsigned long p = *ppos;
     60	void *dst;
     61	int err = 0;
     62	unsigned long total_size;
     63
     64	if (info->state != FBINFO_STATE_RUNNING)
     65		return -EPERM;
     66
     67	total_size = info->screen_size;
     68
     69	if (total_size == 0)
     70		total_size = info->fix.smem_len;
     71
     72	if (p > total_size)
     73		return -EFBIG;
     74
     75	if (count > total_size) {
     76		err = -EFBIG;
     77		count = total_size;
     78	}
     79
     80	if (count + p > total_size) {
     81		if (!err)
     82			err = -ENOSPC;
     83
     84		count = total_size - p;
     85	}
     86
     87	dst = (void __force *) (info->screen_base + p);
     88
     89	if (info->fbops->fb_sync)
     90		info->fbops->fb_sync(info);
     91
     92	if (copy_from_user(dst, buf, count))
     93		err = -EFAULT;
     94
     95	if  (!err)
     96		*ppos += count;
     97
     98	return (err) ? err : count;
     99}
    100EXPORT_SYMBOL_GPL(fb_sys_write);
    101
    102MODULE_AUTHOR("Antonino Daplas <adaplas@pol.net>");
    103MODULE_DESCRIPTION("Generic file read (fb in system RAM)");
    104MODULE_LICENSE("GPL");